2001UL 51 BULLETIN-2001 UL Standard for Safety Power-Operated Pumps for Anhydrous Ammonia and LP-Gas
1995UL 51-1995 UL Standard for Safety Power-Operated Pumps for Anhydrous Ammonia and LP Gas (Eighth Edition; Reprint with Revisions Through and Including March 10@1997)
1992UL 51-1992 Power-operated pumps for anhydrous ammonia and LP-gas